SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66d675f1fd33808aaa6d700d2eb55b3292ad0ea02540f77fb0a7f2aa2734fc9f' 
  AND token = 'N/brftnGD/YzjAuk4PhihNgJIgJmJZM+GVT6FlvFl1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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