SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '323cbc17193d82e7a034964706f14e4e002cf6c80d157f29afb99be338dea166' 
  AND token = 'hgR41X8jRThCBH4ns8jrwnY/QeqsOOJmwu8wDlfkt6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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