SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11eac9e87b16c420c6b6dc174554340846be916d7da1803e245cd18b0591afcf' 
  AND token = '8AjR1ujDtkHSeMt5Yblv/pL0VlRGqytk33BcGa65yZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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