SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1836ff50ebbd97595bbd6e7652d9df646d71176c1cf69497549f18c882c29860' 
  AND token = 'GGtZK/1JbdEP3g+DVWB9F/hKKzSaEke68aRV+QDcDmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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