SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a258e3ddf0a669500be692c70b8c49fcff1878507058539ea7b07ec8e4fc5ba' 
  AND token = 'MjPOzrPmh2td8btYBMWmd5yXcrw7BY/a3S+5+3ITqaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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