SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e60d33b9cd3216e2118ad4615b13281fa57bdc73a9c0e4a02c5779fa38ad80ff' 
  AND token = 'cuNI9L+DCFkotD84OG8hQ+Q7iu/EPAyzf8sl20vGD2c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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