SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc419ccdd28af7dfc10ce62141af235f82219dbecb5cb97b7e1d3e17f8cf0648' 
  AND token = 'GUspRTdnTVPNdACM0Ff+bjmC5YOHjGvH6beGMbXw2Mo=' 
  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"
    }
  }
}