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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dbbddae47bed1dcd31f55bf4723a781e2de4e10095fe1cc1ff419e03d2b838eb' 
  AND token = 'DUm2Tw7g895HZsGYv7XoT1oWS21n1BQQnl1oDn9ElXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}