SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15ad55e1c1620ad15fb97e7f2e39df59a32428b77cd50d0c30cf8294677894d4' 
  AND token = 'WPBDba6U3TVeUCsjkVK7wo/S5z4bUEZOrGA8S7DkC6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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