SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eccc65fed0fc305a0144aff4b9394ae69c3d0db9f4064e23a540bb06c622d936' 
  AND token = 'irTk7MlBVdFbAsultvzqhaO9pw30WfioQGj0qRYZnq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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