SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25bcb21d29828592af8c3244316691ddc9429a49c98926e9e979d11af8553192' 
  AND token = 'FNLq9szv1GNcgRkBiBEEvbAJ90L+gBYDWzHqOuJUaAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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