SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd38faefa1cf06793bfc8e97b84db8a84d342a044f2c5a942b2222c77b719c4bf' 
  AND token = '8LqwCDgu16J0QqDBqgJuTUyhb3zVtC5IQLg+JlU2odI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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