SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16df4a5fda260b62878b7f2f8e92065d6022a4e3b595bba887017a2c876bde3b' 
  AND token = 'hiwQsHv/P77iCyT+tsDICeZtJ0Kg9TtWWKEkSfdpdes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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