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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02c6b99c2534b65a20666363e0df1c04fb607fc9dfcdb91ba35893880230d7dd' 
  AND token = 'kTP3EGis49JAb8j+ffognv5d7y2QzYl+PEEGYpbkFho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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