SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf241eb7906d1ec33565aaa866e09b87c03e6e374742876618716a494781e927' 
  AND token = 'BfNqtFRbpJd05WInzhref+qXVOSipk8B9NRPgIivRGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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