SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1ed5c3eb7ca5fa52577e426ac401f2d057ba8c20961319f440683268cf82c3a2' 
  AND token = 'ixQVYqsoQwQf9HwX4+M+lqxuBtdrlzFYUIVOOmD9G8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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