SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fd1e029ba00b7c8e8bea5a562bbe970e170756bff718ce8076ede2b464c77384' 
  AND token = 'J1Lv6oE8PaUjteBVeEAvIsJFxzbHm1ry2f+JQacye8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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