SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad31a0c3c4163131b36ce8693d3eb1645ba53dd165326e18a34f2d09fa0be148' 
  AND token = '85ZgRtRMKZoS3+W9GDy+bY9t7rqAPrwK01LrLkjlZ6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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