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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68d2182ce78ae7b5763e607ab1108b7560b8df281876003578e52a517eb289ec' 
  AND token = 'iH1SpGU1K04soiUSRiVkimpeJ55TQO+qv6CZkKWJdgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}