SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '789a8f60bff0519efc30ed5d144a3f536686610c5177cc0384b70253dbe963c3' 
  AND token = 'tgm24ydOvxsiLzuZYje7t+4ZCUzIHmt180EKyW6kwiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}