SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62ad31a90654f8306f646ef4f6f0abd63a54693dcebe0feb0a2ca0c6ae8b2569' 
  AND token = 'jFnZQi8nuGuKFex/YkcpA/ykmA44FafJGNspbigZrvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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