SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a342f3b83bb1222fb4fa81fcc844eaf04dcfb9fc9fc370534f4e5c121d1db6' 
  AND token = 'bdV1eCoPH03fePw9cHGV0LUI2hjJ5DsQIU/AUE8Gf40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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