SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2652c4dcb43e03fdd279ed90d50d43a7df0aafc037efb198b79d2da8d6f5453' 
  AND token = 'gYePrgVDqghjl30DVokDcH5joUClh2rqjSPk9gJ789A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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