SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c444ef8cf5589e983919f1266daceb71c31aea37a6e8c701abe7523537507828' 
  AND token = 'GiOWsAZI2/vC/HqvVmOzqRNcUR68Uw///UfY2vBzm4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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