SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52e6e0f223fb3c6409ed62b7972241f2ab14a1fa1670f9c486a921760ff200bd' 
  AND token = 'x9HzNUfu3KCIpwrE+Ng5ONWOvwutmUm0k/O3w8cGL+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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