SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd36a6abebddc047abe35ed65e1846f6d8374a4e8bfe31006d1eebddd2004cc46' 
  AND token = 'qPcBN4/DzNySu8RCTAjw+pEDDSkucnaW0qzcdM1FnM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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