SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0b5a2a71d1591e1441a7a15c854feb49c9811e2efc2bdf948e6e83d74e5740bd' 
  AND token = 'a3MEKDPUJJB5+zYChxgLR9XpDl3QgJK019BqUvX8izk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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