SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c88d42d6c8d92b7bacac453fde7bb21cb1863dd1bb4dd5ad87c0066dde8392de' 
  AND token = 'xC4VvzEOX9wo3lTlaOpnNaDDBs4m7yHqCP5zAtDwsH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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