SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fe34cc822b741245e35913be08766100ca190d71669e9f7ef89eb38ff2a475d' 
  AND token = 'dstcng1FxxRrJJhanHZ+NEOmuYkIc7/Mm0RW5EIqn6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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