SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f09f553d603ffe4c083ce10f798d9cb30d81fdcfe042f397c0366009d1bec834' 
  AND token = 'WewuOcAa81lD2Hs2RCrWBqDVC/VVExBWgMJ15UolBEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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