SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e108312b8fd829c579ffab99e3ac98bfda28d752fc507fa199a04aea220d4c89' 
  AND token = '3OB04wwJRmRmct+2S5Q7tOecf2bE+7spodKSsjUyUYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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