SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e74ad76d7f1fe8400d8da88fc825d5a6251d472ef3f86a07f3c4413a1916a1e6' 
  AND token = 'GDCDCh/JKISDvmApEwdBhS/fjg+OdPjcat+R+OzCWeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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