SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0395734a664be698acfd8361fa0835d5942e62533dd45619cd4914b517cec62f' 
  AND token = '6IAwMJ5ovjr0sUrfvo1Etos5UGk2mgbIru/opG0deFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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