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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a10ccb5eb501f8304fc87ad0fc46d4c42c250f04d4101a098bdaccd0179c6df' 
  AND token = 'r6P0ZsggP8mEoyuhw1itplwF/FcUTDRCkWg0BCUJ9zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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