SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b5c343398727dc78763502edd059fae83dd164b6657a2a93586e44361f5ac96' 
  AND token = 'TOXDv3Ua45kLaCeDMdmxgzL9Z42DL/IV160ZDEKl1xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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