SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18503712285738a6222f63269850c9181df61f913278879a006082a8f980af8f' 
  AND token = 'xbm1npEbNGEs19UKoXdykW8krsV8m2auA0FTdyw6bVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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