SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5446d99b77321baa3725546b257d293ef6571348f25f4982e0218bf45a24e498' 
  AND token = 'aJVXmvI64E00ZZKaZJ6n6noGwd/UxISs8an5bcv+zQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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