SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4163ae4b8094fc8b8f31e1dcf8c3c1e23fbb7a1f0072703093b63e3e92b057b0' 
  AND token = 'dKDVOQP3sNjssusjo06p/Mud63QGGiksCgLJVDzOM50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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