SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5973d3aa91fb1c7ed41ed9fe38e3d6566938470089a7457e6eab1a2651b80b8' 
  AND token = 'TYs1wrEgIbgLNDRWv8qnrBXS5xvNhex6tchSiF2iTxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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