SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a1d36fd433a39178e13053fa9a9e5283a4717046d47b0805e97b58ee8281f4b' 
  AND token = 'oXXpnTgqGwcSRM9UBVceW1K6pARqEu45Lo8Bk2zjn2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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