SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6228ac4d75ad306f0403b923114513a49f95be1696ff85a3fb57e1cfc2ba9750' 
  AND token = 'u8B4CbZ8K/ndcUs2ABx+q2rhiY1eifdXPzLbAPTplbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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