SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0613c4697245645b4bf09eadae046131d7cc7dc250f008af32045661e3a14fac' 
  AND token = 'ZGq+d+0VZimtAVLoUgqz547X5+yK+t3+FARjjzwQKdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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