SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9079baedb7d575da8d783523effe2ca71257794171d943ac24347383f10eb90' 
  AND token = 'tnEFTPSNpP99ujW3hV/pDWj4G1FS/c1/VZwaZJVVIjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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