SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa74efd414a3f65c15ec7a3fd352b3f64e7ee97b9b90096c13520fc8018d977c' 
  AND token = 'vx6Sq+Nsgsl0jnqhXwJAT5vtiHDOFvlNiZQxO/HI7mA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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