SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1623310ab5ac2ec875be3884ef91f681606169f90d659838c6ac863d97b5fbfa' 
  AND token = 'wvxDpRFkENogtBsdU8FbRfRODLfBLDQauDouGIuLIDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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