SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0de1fd519527acda9da8a9bfbe67a51b86c0bc8641e14c214e3902c84402257' 
  AND token = 'rFqX3VUfD0ih3oZ9h9RzVmUQPOjLl+XbzRvPYEx5kZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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