SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de6531ea69bb77a088136eec23f132773d4646fc8194ed3b212b777944ca655e' 
  AND token = 'lUeo6DCw8QBqQLrnjOZPyqaXirOERVjzVfWqu/6rl+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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