SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd166a09a4901acbaf5cc39b74cb3615ed50c481b3110812d68545166b134d1ad' 
  AND token = 'oTAGW9A+QsnjdWBTIyENwQz+iu/qctMh5jdjWZIEaz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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