SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8ea2c130afdf79887c28762ecdf16d7976f7ec41a0e731442875765213a79d' 
  AND token = 'pvbiQHR7+e6Ej2iP+Y8rijmBiW0QwQsL6ruz8pLU1jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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