SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5d8742f6facedae9f171c68bf5b41fe0c19ddbf4a793208625875364b0bcd01c' 
  AND token = 'Z3gK/9sGweIvpJir501NGNzQb8flI5Vg8Kd334PaW5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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