SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efff2a37f3ec3f89f45cbfe66206fd3d0cd204da1893ac4484c51bf3c328ca7f' 
  AND token = 'CgTcuBWs5vYSU1qCvpByeJTVk6cIpnMzk+/krEkKmrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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