SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1e6237bb59587a607385ef09d68abcf5b3a158438db4d7f0349f668c0265e76f' 
  AND token = '7GLRhd4ad7+tywTTa5JWwVfoyC+WD0qk3YmqKcFZIbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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