SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e4cea1f963de30ff081d5ca2dc05f2b0354d18fafecace8672ee0541081fa45' 
  AND token = 'nUBhTC6qrSRLIToDUGyohN8kPSgW1GEEKRHg2q7v6JI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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