SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8250c941c8521ea4d404d2f4fb2babb995c839b0d1ff22cac5a48cec46431ee' 
  AND token = 'eLPXeg0w8Y2BFR0HwAfliZYODFwWp5F2V35XxYgu8yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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