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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15976ddb7c9f010e82ef8a402ad0c0b070fb4dca05f70bc54ab03d7ab43fcfdc' 
  AND token = 'YiKZZ4fA/HiF4PpHyBRPaKLS6gUTEbZSW8aO9/Zz3tA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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