SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66c9d4465bafe60799185c051327ec3ef45f89f2c46b5a025cf799ed68540742' 
  AND token = '7ZYY5W3I9TIJpfILHVp2G8OhBaxawPM1gogukH3z6fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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