SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35f643c3d54a4ba8907501112f00dd926991c9bc0685cf13eba87d7f73505714' 
  AND token = 'RIux/q3DzXsU/MuiYsNkgBis6YhweM7s/xBmZL3c6rc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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