SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c82c8215cab380ff2267e37729700fdfe08ff2bdf48629e569c692a9982fc448' 
  AND token = 'hCOx/Fr7ehxx5Xe8k9GPbJcfmpiXuDyeVvRS5/9RoiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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