SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '666a5e2d062d685b94ae812ae3a2a21c213aafe0926d54b1620e4932adae36a6' 
  AND token = 'b8qqdQ9zyrBNYQekZV9+gcWYWpDla0ZQRSVFn2pupyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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