SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b8392775c76099beb079884fa1bd754415c84f47e880b233119aa4d6158517f' 
  AND token = 'VZ6QF+epOJCwQ8BtOtkQtI5EcK+5uk5hy7SNHyUIUA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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