SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f68aaa6a35a6ecfc0d860869a8b0925350891d3949eb09606702afc21f6a4ec8' 
  AND token = '4Fj1em3D13bB0xx2NUDrZTeg8AQjykYW1zPRtdTa7K8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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