SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '633bdd62a36802e5a5d645d8c379354fca9db1d55da427413177d491977d1c2c' 
  AND token = '3tAWWbGawAVi4jkYz8bPyPKb7t7GPr3wSSjq6MaUlo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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