SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f9eb1bc8bbf819bcd8225f1266d6cd5051b4fd1903b2431b63dc4cde611724dc' 
  AND token = 'sNYYQEfiVjROwCLj8orhGUu5g+QO/7SMT/La2hPLJ9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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