SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'abc64bfdb125eaae9eabdb3ace8b67946f2ca9e4204fc6ac7505f686e23412a0' 
  AND token = 'WzUfqvooCtzhfDPvqzG9cMm2YYudabXr8S//YZl6DDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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