SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '312668782303ada20f1b9100936bbcf1ab0d6a7d8dbf914a8dc7ff448624502f' 
  AND token = '5bl/4G+JUx97yVJH1NQFpAd7QUmqKaKMCDTQe6HL+gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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