SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cc18bcc519fcfd3a52397a05af8a4a9e72c60cfd40e9dbc9b41be566b6cde1f' 
  AND token = 'HEeCtZEXjgQvPuMjalYdx4pjLU4kIQltILpfSM+hJsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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