SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d8bf64115cdd9259a5b44e5ff787c30c9c4f1dff409dd1f163ba3d8bce6ac76' 
  AND token = 'KghInDsH1qO7voFOSxEHQnKIR63CkVQVGfOaSU7v5ZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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