SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4219196b0dbbe27cb82b5e7990636c996b4fce490b6b6fc80ed499ade2403ef2' 
  AND token = 'IFiztifoon2vRctTSV8WM2hSdenKTGSetV3mmyiCD3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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