SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0867cf3b7f8f5a20a5b2ec94348f37cdbb682371a50216be6bc7e0a7425b4d53' 
  AND token = 'piYjuPzbHvBKOKRVvi87QNC5jQkmlM0pKrJVWm+270M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}