SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b83eb9445eeb5c209ca4812bcfc98c508d7009cbd1d3a3415f0c004077262f9a' 
  AND token = '8gAkFVCkW4WIAxKbxmbuerAa0lmLt8Sdwh2aRN4f0dk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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