SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5354ebd4b922781e9414c8d3b72b9b932f486af1062b4fff0899e12d350402e5' 
  AND token = '8hPzmBEOaR2zxqONQfRkijX/uoBudQAX0nkD/R6+aBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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