SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7857a8dac647833a214790c53edae65311c14dd6563306bafa3d7e6cbe54e324' 
  AND token = 'NEEQlJD0/DFaLfB5KklSqjS/z4rSJxkh3KCkHYnhElU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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