SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4297175a7f9ece1ebed552b837c367ca8dc475291f652aa00fa45e17b8443ad9' 
  AND token = 'OXv3yR+WumCkVLyXl/JV9TDjQ2VnS87+3s3wx2sj6ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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