SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af566cf23373ed53caf8f71c9f6c0db87e4110f2d808c14395b36722a57bcf92' 
  AND token = 'UPjFromfU6XtYZpc5iDHu8aGXIR8Ah/5NCYobszQDPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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