SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '263b4e89b1c12dd296535bd0f30e171e4d7446f75c84d23437bae6446f6faf73' 
  AND token = 'ojBoVzcUMZ4yYIyiWDL/xvw+Jj1wogDlt7bNxLzvLIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}