SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '966ff81480883ef5eefcbce56fc4fa9a85fa9764d5bbfd3097c9fcba0b8a2a2e' 
  AND token = 'zKBkCnRQXLK/03LBPm+/aPQHgKCrWpQIsM3C/15JnTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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