SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5aee258714d53651c99e9bda549adfa0cce7697d3c5effd65685f8dc369dc796' 
  AND token = 'tuFoYP8zlxywz1yDvliCTA5HebdN9tK1MYmJn8h/+7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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