SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94bfc7988ab7216e0878fa302c26cc0febe1260c96fa0d63d88081d9368b9460' 
  AND token = '5JACxTArMlZwzZiYnjeEfM6GqmODAMjVmbfZO6ac76g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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