SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec633102e98f4e0674a1135de14cf608f870be99a8f181f3f02380a3bbf423db' 
  AND token = 'AonEo2UKL82XlLY6WU7UPQycimvr9mbqq0jr4P5AikI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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