SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f39832cf332c0940979a3dfe0eccbc4b6dc313c3069ea2564042b64337419033' 
  AND token = 'tK7OyLILacYFI4YCc27pZgfJIgpJ94CLzhcOJ+CuJog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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