SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6175bd6c24122296c7d40f494f44cb3506ad5e555095f588a4d2407579734e89' 
  AND token = 'jUAh6xFishkTEeKOUgkRmBY/w77TbXWwjabvuOlzHfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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