SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '977cfa4af2e2ce3b5e6921886fcc7bd578d4e91c8e032d6a4ee12ae6d1390707' 
  AND token = 'wrYxUzGSSCTgOlxzh8mFZxOXUckqv1jH5+QNdIwx6Ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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