SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef6fe79e6d6a7271126e05845993ef3841858c565cf400efdd4e73d8d6eab2cb' 
  AND token = 'Ru1hXrxZQvVQYprPxQPnFDpVrP/M+GJksXEwF/zMPZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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