SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c468ecaf9f82626552819b076f4b3e4858ef2139faa61a6bbcfd9b0353b091e' 
  AND token = 'elL20hQ2YrhkG9L6ohOCKpRGtyQHcOyd9WqoH6Q7sX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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