SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffa6060a9363f07f708e5303966b3ba23365e21959bc66d5faba25302aee29cb' 
  AND token = 'AUneG9lwYUCiuLzcgWAygIuI5DIMYu0MxlrKF0pr3mA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}