Sandbox

SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '68357b612ecc8a1743570f0fb00a85b51b1572a93eb05e6d1272c36b5c31c387' 
  AND token = 'QaWxOYBqbQ8uNj5DY+cG1dpqnz1luID6ICoaYLcIfJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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