SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '88e9059035cd12c2e1368e6c0379fc6ea52a7c053022322e6edcc45fb728839c' 
  AND token = 'Pp5RjGmLjfnIpNWkSlajjfxPGtcyNTKFeF9LcvhnMJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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