SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '275cdb3b6b4214d280fe80a399396a8893eee27fb457901ea798af0d6361ae9b' 
  AND token = 'tkuUWZjCZudoM8cTKzBn7RqWLIgkv5UD32Ll6tB9Vtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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