SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a182f70da24df9fdd69415a3631c7e8651933ae9815bd4f4e88401cc00f68e4b' 
  AND token = 'kgPvDOLON1tVThpKwdAqZ1HGEmRsNl/e/wsGysNPM5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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